The present disclosure relates to a multilayer ceramic electronic component and a board having the same mounted thereon.
Multilayer ceramic capacitors (MLCCs), types of multilayer electronic component, are used in various types of electronic apparatuses due to inherent advantages thereof, such as small size, high capacitance, and ease of mounting.
Meanwhile, with the electrification of vehicles, the electronic control of such vehicles has become popular. As a result, the number of electrical control units (ECUs) mounted in such vehicles has increased. Further, operation control systems have increased in complexity due to the need for communications and networking between ECUs. Ultimately, each ECU that is directly associated with the safety performance of a vehicle requires high degrees of reliability and durability.
Such ECUs are used in environments in which temperatures are high, sudden changes in temperature can occur, and the ECUs may be exposed to mechanical stresses such as vibrations and shocks for an extended period of time.
The ECUs may each contain one or more MLCCs having excellent thermal or electrical reliability.
Such MLCCs may each include a stack of a plurality of dielectric layers, as well as internal electrodes alternately disposed between the dielectric layers and having different polarities through the stack.
Here, since the dielectric layers respectively have piezoelectric properties, when a direct current (DC) or alternating current (AC) voltage is applied to the MLCC, a piezoelectric phenomenon may occur between the internal electrodes, in which periodic vibrations are generated while the volume of a ceramic body is expanded and contracted, depending on the frequency of the voltage applied thereto.
Such vibrations may be transferred to a board through external electrodes of the MLCC and solders connecting the external electrodes to the board, such that the entirety of the board may act as a sound reflecting surface to generate vibration sound, experienced by users as noise.
The vibration sound may correspond to an audio frequency within a range of 20 Hz to 20,000 Hz, causing listener discomfort. The vibration sound causing listener discomfort, as described above, is known as acoustic noise.
Such acoustic noise may cause a reduction in quality of devices.
Meanwhile, as causes of defects in MLCCs, there may be cracking, or the like, due to the mechanical stress resulting from the vibrations described above. As a result, external moisture may permeate into the MLCC, and thus a level of insulating resistance may be reduced and the ECU may fail or otherwise stop operating.
Thus, a need exists for improving the reliability of MLCCs used in ECUs.